1. Field of the Invention
The present invention relates to a method and apparatus for measuring the resonance frequency of an electric circuit with no undesirable influences or disturbances on the circuit. According to the measurement of the present invention, the resonance frequency, an important parameter for evaluating the circuit, can be determined with low disturbance and high accuracy, so that the present invention greatly contributes to the information/communication and electronics industries.
This application is based on Patent Applications No. Hei 10-287736 filed in Japan, the contents of which are incorporated herein by reference.
2. Description of the Related Art
Generally, a resonance circuit of an electric circuit is designed based on calculated results of the reactance and capacitance of the circuit. However, in most cases, the practical resonance frequency is different from the design value due to the dispersion of characteristics of each element included in the circuit, or to floating capacitance.
Conventionally, an electrically-systemized method has been employed for measuring the resonance frequency, in which a frequency-sweep electromagnetic wave is applied to the resonance section in the target electric circuit, and related reflection or the electric field induced in the resonance section is then measured using a coil. Therefore, the measuring apparatus electrically influences the measured section, and the measured frequency may be different from the real value.